Well everyone is saying prepared solve, so I will offer something else in case that is not what you want to do. Honestly, at your time to improve quickly just do a lot of solves, I found that when I was at your time if I just sat down for like 2 hours and solved my time would drop like 10 seconds by the end, however this often does develop bad habits easier and is probably not as good in the long run as focusing on improving/changing things each practice session. Often some of the things that will make large differences and make you much faster like a week later make you much slower now (ie. switching from beginner method to fridrich, the f2l step will probably slow you down and make your times worse initially but you will get far better in the long run).
Anyway, ya I recommend (if you aren't doing a prepared solve) to just sit down and do a lot of solves. It will improve your recognition time and familiarity with the cube and different cases in your method, which is probably the biggest contributor to your solves at those times, especially if you already have a cube like a Zhanchi. This is because there are two factors that affect how long it takes you to solve the cube: 1. Execution time (how long it takes you to perform the turns/algs and stuff) and 2. Inspection/recognition time (How long it takes you to figure out what you need to be doing or recalling what alg to use).
The second is likely a large part of your times where you sit with the cube looking for pieces (rotating/twisting the cube) and the delay between seeing the piece(s) and executing the algorithm.